New University of Otago-led research has revealed people who use two different inhalers for common chronic lung diseases are more than 50% more likely to have a heart attack than those on just one.
Associate Prof Lianne Parkin, of the Otago Pharmacoepidemiology Research Network, said inhaled long-acting muscarinic antagonists (LAMAs) and long-acting beta-agonists (LABAs) were the main drugs used to treat COPD - the umbrella medical term for emphysema and chronic bronchitis.
While both drugs were bronchodilators used to open airways, they worked in different ways, and in some cases, patients were prescribed both.
The Health Research Council of New Zealand-funded study, recently published in the Journal of Internal Medicine, found that when these drugs were taken together, the patient’s risk of suffering an acute coronary event increased.
Prof Parkin said people with COPD already had a high risk of acute coronary syndrome, so it was important to identify factors that might increase that risk even further.
"It was particularly important to examine the risk associated with the use of LAMAs and LABAs because the clinical benefits of these drugs are modest and people with COPD are more likely to die from coronary events than from respiratory failure.
"We compared the risk of acute coronary syndrome in people who had been given both LAMA and LABA inhalers to treat COPD with the risk in people who had only been given a LAMA inhaler."
In the study’s real-world clinical practice setting, the risk of acute coronary syndrome was more than 50% higher in patients with COPD who used two long-acting bronchodilators rather than one, she said.
In absolute terms, about eight people per year out of every 1000 using both a LAMA and LABA for COPD experienced an acute coronary event that they would not have had if they had just used a LAMA.
Co-author and respiratory physician Dr Jack Dummer said the findings were something for people to consider when weighing up the potential benefits and harms of escalating treatment from one to two bronchodilators.
